Flexible-surfaced bone conduction hearing aid unit



May 24, 1949. H. s. KNOWLES 2,470,933

SURFACED BONE CONDUCTION HEARING AID UNIT FLEXIBLE- Filed June 5, 1944 MATERIAL PL AST'IG NEAR TNV'ENTORI HUGH S. KNOWLES fihvxg nFs His ATTORNEY of the bone conduction element arranged to transmit vibratidri's to the aiiditory fierve through-the boiiy struture df the Patented May 24, 1949 f remen:scenicmp onereosnucnou HEARING AIDUNTT Illinois awerporatiom *Of 1 invention relates t caring aid eai plidnes p' -having-a vibi atile head of a user.

An object of the present invention to provide a bone conduction earphone in which improved means are provided for holding the earphone in operative position against the users head and in which the contacting surface is more comfortable to the user and provides efficient sound transmission.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in con nection with the accompanying drawings, in which:

Figure 1 shows an assembly incorporating a hearing aid earphone which embodies the present invention,

Figure 2 shows a sectional view of the earphone of Figure 1, and,

Figure 3 shows a modification of the earphone of Figure 2.

As illustrated in Fig. l, a casing I is arranged to press against a suitable portion of the user's head, for example, the mastoid bone, by mounting the composite earphone, or receiver, 2 on a suitable headband 3 having a resilient extension 4 of which a supported end is fastened to the curved head engaging resilient strap 5 of headband 3 and of which the free end is fastened to support pin 6.

With this arrangement, the pressure exerted by casing I of earphone 2 on the users head is almost entirely dependent upon the resilience of extension 4, and is relatively constant, even though the resilient band 5 (arranged to contact the users head and hold the receiver 2 in operative condition) has its opposite head engaging ends I and 8 stretched difierently in use by persons having heads of different sizes.

Extension 4 is fastened to resilient strap 5, for example, by means of rivets 9 and may be fastened to support pin 6 by means of a screwthreaded connection (not shown) between pin 6 and the end of extension 4. A feature of the particular headband shown in Fig. l is that a receiver, or earphone, of the bone conduction type is held in operative position with the headband extending around over the top of the users head "sc -that the us'ers 'norinal activities infiuence in a '3 e a suitalbl pdrtitin karmic-n relatively smelt degree "the prefssure ef -casing I tarea eeiiees the ieiide ncymf casing r-a erawi" 1 face l2.

ofi the mastoid bone, and controls the low frequency response by giving more uniform compliance between the users head and casing I.

Fig. 2 shows an enlarged view of a section through an earphone 2 of Figure 1, and as shown herein the side of casing I arranged to contact the users mastoid bone or similar portion of his head is provided with a recessed portion I0 into which is cemented or bonded a layer of elastic material II having a concave head engaging sur- The nature of the elastic material H and the contour of its surface I2 minimizes the tendency of the casing I to crawl when in use and improves the energy transmitting contact between casing I and the users head.

In the modified arrangement shown in enlarged view in Fig. 3, the side of the casing l arranged to contact the users mastoid bone or similar portion of his head is provided with a recessed portion I3 enclosed by a nonporous flexible fabric material I4 which confines within said recessed portion a material I5 having the property of being solid at ordinary room temperatm'es but which is somewhat plastic at temperatures of about 98 Fahrenheit, the ends I6 and ll of the fabric It being anchored, such as by molding'said ends in the casing I. Materials such as material I5 which is solid at room temperatures of about Fahrenheit and somewhat plastic at body temperatures of the order of 985 Fahrenheit are plentiful and. they comprise organic compounds such as greases, waxes, etc. One of the advantages residing in the use of the arrangement shown in Fig. 3 is that after fabric I4 is in resilient contact with the users skin for a short time interval the material I'5 becomes plastic, due to body heat of the user, and the contour of fabric [4 corresponds to the contour of the users anatomy which is contacted. It is thus evident that a good contact exists between the casing proper and the users anatomy.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. In a hearing aid unit of the bone conduction type, a casing, said casing having a recess and a surface of moldable material arranged within said recess to be molded into a concave surface in contact with skin over a users mastoid bone.

2. In a bone conduction earphone, a casing having the contact surface with a recessed portion, a flexible nonporous thermally conducting fabric enclosing said recessed portion, and a material in said hollow portion, substantially solid at temperatures in the order of 70 near body temperatures whereby contact of said fabric with a users skin causes the material and fabric to conform in shape to that portion of the users body which is contacted.

3. In a hearing aid unit of the bone conduc tion type, a casing having a recess therein, and flexible material in said recess in sufiicient amount to touch a users mastoid bone when said casing is placed thereover and of suflicient flexibility that such contact is over a substantial area.

said material being Fahrenheit but plastic at temperatures- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 728,003 Pfanschmidt et a1. May 12, 1903 742,287 Casper Oct. 27, 1903 957,982 Moon May 17, 1910 1,579,412 Stenberg Apr. 6, 1926 1,713,206 Young et a1 May 14, 1929 1,876,164 Pridham Sept. 6, 1932 1,912,078 Hunter May 30, 1933 2,062,372 Nicholides Dec. 1, 1936 2,143,130 Nicholides Jan. 10, 1939 2,220,269 Patzold Nov. 5, 1940 

